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The Sun is the source of energy for most of life on Earth. As a star, the Sun is heated to high temperatures by the conversion of nuclear binding energy due to the fusion of hydrogen in its core. This energy is ultimately transferred (released) into space mainly in the form of radiant (light) energy.

In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. Energy is a conserved quantity; the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton.

Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object's position in a force field (gravitational, electric or magnetic), the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an object's temperature.

Mass and energy are closely related. Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale.

Living organisms require available energy to stay alive, such as the energy humans get from food. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earth's climate and ecosystem are driven by the radiant energy Earth receives from the sun and the geothermal energy contained within the earth.

Selected article

Renewable energy in Iceland has supplied over 70% of Iceland's primary energy needs since 1999 - proportionally more than any other country - and 99.9% of Iceland's electricity is generated from hydroelectricity and geothermal power. In 1998 the Icelandic Parliament committed to convert the national vehicle and fishing fleets to hydrogen fuel produced from renewable energy by 2050. This would make Iceland the first completely energy-independent country in the world to use 100% renewable energy sources.

Iceland's location on the Mid-Atlantic Ridge makes it one of the most tectonically active places in the world, with over 200 volcanoes and over 20 high-temperature steam fields. Geothermal energy for heating was first used in 1907 when a farmer piped steam from a hot spring into his house. In 1930, the first pipeline was constructed in Reykjavík, heating two schools, 60 homes, and the main hospital. In 1943, the first geothermal district heating company started. Geothermal power now heats 89% of the nation's houses, provides around 19% of electricity generation and over 54% of primary energy. The first hydroelectric plant was built in 1904 and produced 9 kW of power. Hydropower now provides 81% of Iceland's electricity supply.

Imported oil provides most of Iceland's remaining energy. Replacing this with hydrogen was first suggested after the 1970s energy crisis, but the idea was not adopted until 1998. Iceland's small size makes it ideal for testing the viability of hydrogen as a fuel source for the future, while the plentiful renewable energy sources can be harnessed for its production. Iceland participates in international hydrogen fuel research and development programs, and many countries are following the nation's progress.

As a result of its transition to renewable energy, Iceland is ranked 53rd in the list of countries by carbon dioxide emissions per capita in 2003, emitting 62% less than the United States despite using more primary energy per capita. Read more...

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Photo credit: Jon Sullivan
Photosynthesis is a complex energy transformation process in which sunlight, carbon dioxide and water are converted to chemical energy by living organisms.

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  • According to research by the IPCC, government funding for most energy research programmes has been flat or declining for nearly 20 years, and is now about half the 1980 level?
Cyclone Catarina from the ISS on March 26 2004.JPG

Selected biography

Sheikh Ahmed Zaki Yamani (born 1930) was Saudi Arabia's Minister of Oil (Petroleum) and Mineral Resources from 1962 until 1986, and a minister in OPEC for 25 years. He is best known for his role in the 1973 oil crisis, when OPEC quadrupled the price of crude oil.

Yamani gained a degree from Harvard Law School and a master's in Comparative Jurisprudence from New York University. After working in the Saudi Ministry of Finance, in 1958 be became a legal advisor to Faisal, then Crown Prince and Prime Minister, until Faisal's resignation in 1960. After Faisal's return to government, in 1962 Yamani replaced Abdallah Tariki as Oil Minister, playing an important role in the development of OPEC. During the 1967 Arab–Israeli War Yamani spoke against the use of an Arab oil embargo. The following year he lead the founding of the Organization of Arab Petroleum Exporting Countries.

When Arab–Israeli hostilities resumed with the 1973 Yom Kippur War, the pressure to join the other Arab states, who wished to use oil to change the apparent pro-Israeli policy of the United States government, was irresistible. Yamani's proposal of increasing monthly cuts in production was accepted and, together with a later embargo against the US and the Netherlands and a quadrupling of the oil price, severely affected the economies of all western nations. Despite this, by resisting more extreme proposals Yamani became increasingly seen as pro-American in the Arab world. Read more...

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